Re: PR61919: Invalid rtx sharing in tree-outof-ssa.c

[Richard Biener <richard dot guenther at gmail dot com>]

On Sun, Jul 27, 2014 at 8:01 PM, Richard Sandiford
<rdsandiford@googlemail.com> wrote:
> PR 61919 is another ripple from the patch to take advantage of rtx
> sharing rules when instantiating virtual registers.  In this case
> the invalid sharing is coming from tree-outof-ssa.c, where the same
> MEM rtx is being used in several moves.  (Note that despite the name,
> partition_to_pseudo maps to stack slot MEMs as well as pseudos.)
>
> Tested on x86_64-linux-gnu.  Also tested by Andreas on ia64,
> where the testsuite regression showed up.  OK to install?

Ok.

Thanks,
Richard.

> Thanks,
> Richard
>
>
> gcc/
>         PR middle-end/61919
>         * tree-outof-ssa.c (insert_partition_copy_on_edge)
>         (insert_value_copy_on_edge, insert_rtx_to_part_on_edge)
>         (insert_part_to_rtx_on_edge): Copy partition_to_pseudo rtxes before
>         inserting them in the insn stream.
>
> Index: gcc/tree-outof-ssa.c
> ===================================================================
> --- gcc/tree-outof-ssa.c        2014-07-26 21:14:51.074755469 +0100
> +++ gcc/tree-outof-ssa.c        2014-07-26 21:14:51.590759910 +0100
> @@ -260,8 +260,8 @@ insert_partition_copy_on_edge (edge e, i
>      set_curr_insn_location (locus);
>
>    var = partition_to_var (SA.map, src);
> -  seq = emit_partition_copy (SA.partition_to_pseudo[dest],
> -                            SA.partition_to_pseudo[src],
> +  seq = emit_partition_copy (copy_rtx (SA.partition_to_pseudo[dest]),
> +                            copy_rtx (SA.partition_to_pseudo[src]),
>                              TYPE_UNSIGNED (TREE_TYPE (var)),
>                              var);
>
> @@ -274,7 +274,7 @@ insert_partition_copy_on_edge (edge e, i
>  static void
>  insert_value_copy_on_edge (edge e, int dest, tree src, source_location locus)
>  {
> -  rtx seq, x;
> +  rtx dest_rtx, seq, x;
>    enum machine_mode dest_mode, src_mode;
>    int unsignedp;
>    tree var;
> @@ -289,7 +289,8 @@ insert_value_copy_on_edge (edge e, int d
>        fprintf (dump_file, "\n");
>      }
>
> -  gcc_assert (SA.partition_to_pseudo[dest]);
> +  dest_rtx = copy_rtx (SA.partition_to_pseudo[dest]);
> +  gcc_assert (dest_rtx);
>
>    set_location_for_edge (e);
>    /* If a locus is provided, override the default.  */
> @@ -300,9 +301,9 @@ insert_value_copy_on_edge (edge e, int d
>
>    var = SSA_NAME_VAR (partition_to_var (SA.map, dest));
>    src_mode = TYPE_MODE (TREE_TYPE (src));
> -  dest_mode = GET_MODE (SA.partition_to_pseudo[dest]);
> +  dest_mode = GET_MODE (dest_rtx);
>    gcc_assert (src_mode == TYPE_MODE (TREE_TYPE (var)));
> -  gcc_assert (!REG_P (SA.partition_to_pseudo[dest])
> +  gcc_assert (!REG_P (dest_rtx)
>               || dest_mode == promote_decl_mode (var, &unsignedp));
>
>    if (src_mode != dest_mode)
> @@ -312,15 +313,14 @@ insert_value_copy_on_edge (edge e, int d
>      }
>    else if (src_mode == BLKmode)
>      {
> -      x = SA.partition_to_pseudo[dest];
> +      x = dest_rtx;
>        store_expr (src, x, 0, false);
>      }
>    else
> -    x = expand_expr (src, SA.partition_to_pseudo[dest],
> -                    dest_mode, EXPAND_NORMAL);
> +    x = expand_expr (src, dest_rtx, dest_mode, EXPAND_NORMAL);
>
> -  if (x != SA.partition_to_pseudo[dest])
> -    emit_move_insn (SA.partition_to_pseudo[dest], x);
> +  if (x != dest_rtx)
> +    emit_move_insn (dest_rtx, x);
>    seq = get_insns ();
>    end_sequence ();
>
> @@ -356,7 +356,7 @@ insert_rtx_to_part_on_edge (edge e, int
>       mems.  Usually we give the source.  As we result from SSA names
>       the left and right size should be the same (and no WITH_SIZE_EXPR
>       involved), so it doesn't matter.  */
> -  seq = emit_partition_copy (SA.partition_to_pseudo[dest],
> +  seq = emit_partition_copy (copy_rtx (SA.partition_to_pseudo[dest]),
>                              src, unsignedsrcp,
>                              partition_to_var (SA.map, dest));
>
> @@ -390,7 +390,7 @@ insert_part_to_rtx_on_edge (edge e, rtx
>
>    var = partition_to_var (SA.map, src);
>    seq = emit_partition_copy (dest,
> -                            SA.partition_to_pseudo[src],
> +                            copy_rtx (SA.partition_to_pseudo[src]),
>                              TYPE_UNSIGNED (TREE_TYPE (var)),
>                              var);
>